collab: Add support for subscribing to Zed Pro trials (#28812)

This PR adds support for subscribing to Zed Pro trials (and then
upgrading from a trial to Zed Pro).

Release Notes:

- N/A

crates/collab/src/db/queries/billing_subscriptions.rs

@@ -62,11 +62,14 @@ impl Database {
             billing_subscription::Entity::update(billing_subscription::ActiveModel {
                 id: ActiveValue::set(id),
                 billing_customer_id: params.billing_customer_id.clone(),
+                kind: params.kind.clone(),
                 stripe_subscription_id: params.stripe_subscription_id.clone(),
                 stripe_subscription_status: params.stripe_subscription_status.clone(),
                 stripe_cancel_at: params.stripe_cancel_at.clone(),
                 stripe_cancellation_reason: params.stripe_cancellation_reason.clone(),
-                ..Default::default()
+                stripe_current_period_start: params.stripe_current_period_start.clone(),
+                stripe_current_period_end: params.stripe_current_period_end.clone(),
+                created_at: ActiveValue::not_set(),
             })
             .exec(&*tx)
             .await?;

crates/collab/src/db/tables/billing_subscription.rs

@@ -43,6 +43,10 @@ impl ActiveModelBehavior for ActiveModel {}
 pub enum SubscriptionKind {
     #[sea_orm(string_value = "zed_pro")]
     ZedPro,
+    #[sea_orm(string_value = "zed_pro_trial")]
+    ZedProTrial,
+    #[sea_orm(string_value = "zed_free")]
+    ZedFree,
 }
 
 /// The status of a Stripe subscription.